Spherical Aberration Corrector, Method of Spherical Aberration Correction, and Charged Particle Beam Instrument

A spherical aberration corrector for use with a charged particle beam instrument for obtaining an image and a diffraction pattern, said spherical aberration corrector comprising:

• a hexapole field generating portion for producing plural stages of hexapole fields;
• a quadrupole field superimposing portion for superimposing a quadrupole field on at least one of the plural stages of hexapole fields to correct deviation of the circularity of at least one of the image and diffraction pattern;
• and
• a deflection portion for deflecting a charged particle beam.

A spherical aberration corrector for use with a charged particle beam instrument for obtaining an image and a diffraction pattern, said spherical aberration corrector comprising:

• a hexapole field generating portion for producing plural stages of hexapole fields;
• a deflecting field superimposing portion for superimposing a deflecting field on at least one of the plural stages of hexapole fields to correct deviation of the circularity of at least one of the image and diffraction pattern;
• and
• a deflection portion for deflecting a charged particle beam.

The method of spherical aberration correction implemented in a charged particle beam instrument for obtaining an image and a diffraction pattern, said method comprising the steps of:

• producing plural stages of hexapole fields;
• superimposing an octopole field on at least one of the hexapole fields to correct deviation of the circularity of at least one of said image and diffraction pattern;
• and
• deflecting a charged particle beam to adjust the tilt of the beam within the hexapole field such that four-fold astigmatism induced by the octopole field is corrected.

A method of spherical aberration correction implemented in a charged particle beam instrument for obtaining an image and a diffraction pattern, said method comprising the steps of:

• producing plural stages of hexapole fields;
• superimposing a quadrupole field on at least one of the hexapole fields to correct deviation of the circularity of at least one of said image and diffraction pattern;
• and
• deflecting a charged particle beam to adjust the tilt of the beam within the hexapole field such that star aberration induced by the quadrupole field is corrected.

A method of spherical aberration correction implemented in a charged particle beam instrument for obtaining an image and a diffraction pattern, said method comprising the steps of:

• producing plural stages of hexapole fields;
• superimposing a deflecting field on at least one of the hexapole fields to correct deviation of the circularity of at least one of said image and diffraction pattern;
• and
• deflecting a charged particle beam to adjust the tilt of the beam within the hexapole field such that star aberration induced by the deflecting field is corrected.